I see dead people

I've read that pregnancy can bring on crazy dreams. I have pretty insane dreams anyway, but in the last week, I've dreamt three different times about childhood friends of mine who are dead. One died in a car accident and one in a plane crash. But in my dreams they're alive and just hanging around, doing whatever I happen to be doing in the dream (at a party, for example, or riding in the car). In the dreams, I'm aware of the fact that they are dead and aren't supposed to be there, but I don't say anything to them about it. And then I wake up very disturbed and sad. I keep waiting for a dream about Kristin, but it hasn't happened yet.